Adiponectin deficiency exacerbates age-related hearing impairment

Area of Science:

• Otolaryngology
• Endocrinology
• Gerontology

Background:

• Obesity-related disorders are linked to age-related hearing impairment (ARHI).
• Adiponectin (APN) offers protection against obesity-related conditions like endothelial dysfunction.
• The role of APN in ARHI remains to be fully elucidated.

Purpose of the Study:

• To investigate the impact of Adiponectin (APN) on age-related hearing impairment (ARHI).
• To determine if APN deficiency exacerbates hearing loss and if APN supplementation can prevent it.

Main Methods:

• Comparison of hearing impairment, cochlear blood flow, and stria vascularis capillary density between APN-knockout (APN-KO) and wild-type (WT) mice.
• Assessment of apoptosis in the cochlea using TUNEL staining.
• In vitro studies using auditory HEI-OC1 cells under hypoxic conditions.
• Clinical analysis of plasma APN levels in human subjects with ARHI.

Main Results:

• APN-KO mice exhibited exacerbated hearing impairment, reduced cochlear blood flow, and decreased capillary density in the stria vascularis.
• APN-KO mice showed increased apoptosis in the cochlea and subsequent hair cell loss.
• APN supplementation prevented hearing impairment in APN-KO mice.
• In vitro, APN reduced apoptosis in auditory cells under hypoxia.
• Lower plasma APN levels were observed in humans with ARHI, with APN identified as an independent predictor.

Conclusions:

• Adiponectin (APN) plays a crucial role in preventing age-related hearing impairment (ARHI).
• APN deficiency contributes to cochlear dysfunction and apoptosis, leading to hearing loss.
• Maintaining adequate APN levels may be a therapeutic strategy for ARHI.